Heretofore, the “ETWS (Earthquake and Tsunami Warning System)”, the “PWS (Public Warning System)”, and the like have been known as systems to transmit emergency information to multiple mobile stations.
Use of a SIB (System Information Block) on a broadcast channel (BCCH: Broadcast Control Channel) to transmit emergency information to multiple mobile stations has been considered for such “ETWS/PWS”.
In a conventional “ETWS/PWS”, however, a radio base station is configured to transmit multiple types of system information (SIB1 to SIB8) repeatedly within a modification period (MP). This causes a problem that, even if detecting occurrence of emergency information, the radio base station cannot make notification of the emergency information in the current modification period MP(n), and cannot transmit the emergency information until the next modification period MP(n+1) starts.